The present invention relates generally to writing instruments and more particularly to liquid ink writing units or refills therefor.
Liquid ink writing units are used comprising a cartridge with a capillary body charged with ink and an ink feed member having increasing capillarity rate interposed between the cartridge and a writing tip which is either the end of the ink feed member or a ballpoint.
In known writing units the ink accumulating capillary body of the cartridge is in communication with the atmosphere through its lower or front end so that the ink evaporates relatively quickly.
Further, the pressure or impacts which the writing instrument undergoes during use, sometimes causes the displacement or deformation of the parts of the writing unit which may adversely affect the operation thereof.